Apparatus for line printing



May 6, 1969 Filed May 17, 1967 TADASHI SUGIMOTO APPARATUS FOR LINEPRINTING F/G.l

AREA 1 Sheet rrAs DRUM ii FT W l/AMMUPS /2 M 4 l /24 ms /2c 40 (04 J) 4)#4444152 4 CONTROL uA/lr l3 '-40COL 55 75C TADASH-l SUGIMOTO APPARATUSFOR LINE PRINTING R v f .3

kn nw mm l l I May 6, 1969 Filed May 17, 1967 y 5, 1969 TADASHI SUGIMOTO3,442,206

APPARATUS FOR LINE PRINTING a Filed May 17, 1967 7 Sheet 3 of 8 COMPUTER8/ TYPE C005 4M0 T/ME PULSE GENERATOR 57 May 6, 1969 TADASHI SUGIMOTOAPPARATUS FOR LINE PRINTING y 14969 TADASHI susmo'ro 3,442,206

APPARATUS FOR LINE PRINTING Filed May 17, I967 Sheet 6 of a y 1969TADASHI suemo'ro 3,442,206

APPARATUS FOR LINE PRINTING Sheet Filed May 17, 1967 Q m w v m m N m M Qm ND M Q h w m x h A 0 Q m m w m N J m WnNaW o "a wnmwom Q vmr o mmuomwmwmomom TNYQ QWQQQQ United States Patent U.S. Cl. 101--93 3 ClaimsABSTRACT OF THE DISCLOSURE A plurality of printing hammers of lineprinting apparatus are successively operated in groups to print groupsof columns in succession. The number of columns in each of the groups isless than the total number of columns and is the same in each of thegroups.

Description of the invention The present invention relates to lineprinting. More particularly, the invention relates to a method andapparatus for line printing.

Line printers of known type utilize printing hammers and hammeractuating magnets. The hammer actuating magnets are controlled inoperation, actuation or energization to control the operation of thehammers and thereby to control the printing. It is often desirable toincrease the printing speed of the line printer, and there have beenmany different types of printing apparatus and printing methods. As theprinting speed is increased and the performance enhanced, the cost ofthe apparatus increases. There are, however, small-sized electroniccomputers which utilize in their inputs and/ or outputs smallsized lowspeed printers. The line printers utilized with the small-sizedcomputers must be of low cost in order to raise the ratio of theperformance of the equipment relative to its cost.

The principal object of the present invention is to provide a new andimproved method and apparatus for line printing. The method andapparatus of the present invention for line printing are suitable foroperation with smallsized computers. The apparatus of the presentinvention for line printing is of small size and of low cost andoperates at low speed. The apparatus of the present invention for lineprinting is efficient, effective and reliable in operation. Theapparatus of the present invention for line printing utilizesconventional known components and conventional known line printingequipment.

In accordance with the present invention, the method of line printing aplurality of columns comprises printing groups of columns in succession.The number of columns in each of the groups of columns is less than thetotal number of the plurality of columns. The number of columns in eachof the groups of columns is the same. The groups of columns are printedin a line on a recording medium by printing the groups of columns insuccession and upon completion of the printing of the groups of columnsthe recording medium is fed to its next line. The groups of columns areprinted in a line on a recordingmedium by printing only determined onesof the groups of columns to be printed, bypassing the others of thegroups of columns not to be printed and feeding the recording medium toits next line at free points of time.

In accordance with the present invention, line printing apparatuscomprises printing apparatus for printing a plurality of columns. Theprinting means includes a plurality of printing hammers. Hammer controlapparatus controls the operation of the printing apparatus to suc-3,442,206 Patented May 6, 1969 cessively operate the plurality ofprintnig hammers in groups to print groups of columns in succession.

The hammer control apparatus comprises a plurality of hammer-controllingelectromagnets each controlling a corresponding one of the printinghammers. Switches are interposed between the electromagnets and a powersupply source for selectively switching one group of electromagnets at atime to the power supply source. Each group of electromagnets is thesame as each group of corresponding printing hammers. The switches are aplurality of semiconductor controlled rectifiers and the number ofsemiconductor controlled rectifiers is the same as the number of thegroups.

In order that the present invention may be readily carried into effect,it will now be described with reference to the accompanying drawings,wherein:

FIG. 1 is a schematic block diagram illustrating the principle ofoperation of the apparatus of the present invention and the method ofthe present invention;

FIG. 2 is a circuit diagram illustrating the operation of the apparatusof the present invention and the method of the present invention;

FIG. 3 is a block diagram of an embodiment of the apparatus of thepresent invention;

FIGS. 4A and 4B are time charts illustrating the operation of theembodiment of FIG. 3;

FIG. 5 is a block diagram of a modification of the apparatus of thepresent invention;

FIGS. 6A and 6B are time charts illustrating the operation of themodification of FIG. 5;

FIG. 7 is a schematic side view of an embodiment of a line printer;

FIG. 8 is a perspective view of a type wheel;

FIG. 9 is a developed view of the type surface of a type wheel; and

FIG. 10 is an illustration of the printed data on the printing paper.

FIG. 1 illustrates the principle of operation of the apparatus of thepresent invention. The components of FIG. 1 may comprise any suitablecomponents known in the art for performing the indicated functions. Atype drum 11 is rotatably mounted and may comprise, for example, 120columns. Print hammers 12 are mounted in operative proximity with thetype drum 11 and function to print 120 columns in a known manner.

A hammer control unit 13 is electrically connected to the electromagnetsof the print hammers 12. The hammer control unit 13 functions tooperate, actuate or energize 40 print hammers at a time to thereby print40 columns. A shift register 14 is electrically connected to the hammercontrol unit 13 and functions to store 40 bits of control data orinformation.

In the apparatus of FIG. 1, although the type drum 11 is divided intothree equal areas 1, 2 and 3, each being a cylindrical surface areaequal to one-third the cylindrical surface area of said drum, said drummay be divided into any suitable number n of equal cylindrical surfaceareas. The number of print hammers 12, and therefore columns printedunder the control of the hammer control unit 13, controlled by saidhammer control unit, corresponds to the number of equal areas into whichthe drum 11 is divided. The shaft register 14 stores a number of bits ofcontrol data equal to the number of columns printed at one time underthe control of the hammer control unit 13.

In accordance with the present invention, each group ofhammer-controlling electromagnets is driven or controlled in successionby the hammer control unit 13. Thus, in accordance with the method ofthe present invention, a number of columns equal to the total number ofcolumns of the type drum 11 divided by n, is first printed by the hammercontrol unit 13, the next succeeding equal number of columns is nextprinted under control of the hammer control unit 13, and so on, untilall the columns of the type drum are printed. For purposes ofillustration, the area of the type drum 11 is divided into three equalareas, so that n:3, and the 120 columns of said type drum are dividedinto three equal groups of 40 columns each. The 40 columns of area 1 ofthe type drum 11 are first printed under the control of the hammercontrol unit 13, the 40 columns of area 2 of said type drum are thenprinted under the control of said hammer control unit, and the 40columns of area 3 of said type drum are then printed under the controlof said hammer control unit. During each printing of the columns of anarea of th type drum 11, said type drum is rotated or driven in asuitable manner by suitable known apparatus, not shown in the figures.

During the printing operation, the printing paper or recording medium,not shown in FIG. 1, which is interposed between the print hammers 12and the type drum 11, remains in the same position, whereas said typedrum rotates three times for the printing of a single line. In order toprint the 40 columns of area 1 of the type drum 1 a switch 15A isclosed, either manually or automatically, to close a circuit between thehammer control unit 13, the first group 12A of 40 print hammers and asource of voltage E. In order to print the 40 columns of area 2 of thetype drum 11, a switch 15B is closed, either manually or automatically,to close a circuit between the hammer control unit 13, the second group12B of 40 print hammers and the source of voltage E. In order to printthe 40 columns of area 3 of the type drum 11, a switch 150 is closed,either manually or automatically, to close a circuit between the hammercontrol unit 13, the third group 120 of 40 print hammer and the sourceof voltage E. Only one of the switches 15A, 15B and 150 is closed at atime, and said switches are operated in sequence.

FIG. 2 illustrates the operation of the hammer-controllingelectromagnets under the control of the hammer control unit 13. In FIG.2, the hammer-controlling electromagnets are not all illustrated, butare indicated only by the first and last of each group of saidelectromagnets. Thus, in FIG. 2, the hammer-controlling electromagnetsof the first of the three groups of said electromagnets are representedby the first electromagnet 16-1 and the last of said electromagnets16-h. In the present example, I: equals 40. The hammer-controllingelectromagnets of the second of the three groups of said electromagnetsare represented by one first electromagnet 17-1 and the last of saidelectromagnets 17-h. The hammer-controlling electromagnets of the thirdof the three groups of said electromagnets are represented by the firstelectromagnet 18-1 and the last of said electromagnets 18-h.

The hammer control unit 13 is indicated principally in block form.However, a first control transistor 19-1 and a last control transistor19-h are shown as included in the hammer control unit 13 in order toenhance the description of the operation of said unit. Each of thecontrol transistors 19-1 to 19-h of the hammer control unit 13 controlsa corresponding one of the hammer-controlling electromagnets of each ofthe n groups of said electromagnets. Thus, the control transistor 19-1is connected in series with the first hammer-controlling electromagnet16-1, 17-1 and 18-1 of each of the three groups of said electromagnets.The control transistor 19-h is connected in series with the lasthammer-controlling electromagnets 16-h, 17-h and 18-h of each of thethree groups of said electromagnets.

The series connection of the corresponding control transistor of thehammer control unit 13 and the corresponding hammer-controllingelectromagnets is through corresponding diodes which prevent a currentflow in th opposite direction. Thus, the collector electrode of thcontrol transistor 19-1 is connected in common to one end of the windingof each of the electromagnets 16-1,

4 17-1 and 18-1 via a common lead 21, leads 22, 23 and 24 andcorresponding diodes 25, 26 and 27. The diode 25 is connected in thelead 22 with its anode connected to the common lead 21 and with itscathode connected to the aforementioned end of the winding of theelectromagnet 16-1. The diode 26 is connected in the lead 23 with itsanode connected to the common lead 21 and with its cathode connected tothe aforementioned end of the winding of the electromagnet 17-1. Thediode 27 is connected in the lead 24 with its anode connected to thecommon lead 21 and with its cathode connected to the aforementioned endof the winding of the electromagnet 18-1. The emitter electrode of thecontrol transistor 19-1 is connected to ground via a lead 28.

The collector electrode of the control transistor 19-h is connected incommon to one end of the winding of each of the electromagnets 16-h,17-h and 18-h via a common lead 29, leads 31, 32 and 33 andcorresponding diodes 34, and 36. The diode 34 is connected in the lead31 with its anode connected to the common lead 29 and with its cathodeconnected to the aforementioned end of the winding of the electromagnet16-h. The diode 35 iS connected in the lead 32 with its anode connectedto the common lead 29 and with its cathode connected to theaforementioned end of the winding of the electromagnet 17-h. The diode36 is connected in the lead 33 with its anode connected to the commonlead 29 and with its cathode connected to the aforementioned end of thewinding of the electromagnet 18-h. The emitter electrode of the controltransitsor 19-h is connected to ground via a lead 37.

The emitter electrode of each of the 40 control transistors 19-1 to 19-hof the hammer control unit 13 is connected to one terminal of anelectrical power supply source E via a common ground line 38 and a lead39. The other terminal of the power source E is connected in common tothe cathode of each of three semiconductor controlled rectifiers or SCRs41A, 41B and 41C via a common lead 42 and leads 43, 44 and 45,respectively. The anode of the first SCR 41A is connected in common tothe other end of the winding of each of the hammer-controllingelectromagnets 16-1 to 16-h of the first group of said electromagnetsvia a common lead 46 and branch leads 47-1 to 17-11, respectively. Theanode of the second SCR 41B is connected in common to the other end ofthe winding of each of the hammer-controlling electromagnets 17-1 to17-h of the second group of said electromagnets via a common lead 48 andbranch leads 49-1 to 49-h, respectively. The anode of the third SCR 410is connected in common to the other end of the winding of each of thehammer-controlling electromagnets 18-1 to 18-h of the third group ofsaid electromagnets via a com mon lead 51 and branch leads 52-1 to 52-h,respectively.

Each of the hammer-controlling electromagnets is shunted by a clampingdiode. Thus, a clamping diode 53 is shunted across thehammer-controlling electromagnet 16' 1. A clamping diode 54 is shuntedacross the hammer-com trolling electromagnet 17-1. A clamping diode 55is shunted across the hammer-controlling electromagnet 18-1. A clampingdiode 56 is shunted across the hammer-controlling electromagnet 16-h. Aclamping diode 57 is shunted across the hammer-controlling electromagnet17-Iz. A clamping =diode 58 is shunted across the hammer-controllingelectromagnet 18-h.

Each of the first, second and third SCRs 41A, 41B and 51C may compriseany suitable SCR known in the art, such as, for example, those describedin considerable detail in the Silicon Controlled Rectifier Manual, thirdedition, 1964, General Electric Company, Auburn, N.Y. Each SCR includesa gate or control electrode which is utilized to control the conductivecondition of such SCR.

A switching control transistor 59 is connected in the common ground line38. The emitter electrode of the switching control transistor 59 isconnected to the ground terminal of the electrical power source E andthe collector electrode of said switching control transistor isconnected in common via a lead 61, a control resistor 62, and leads 63,64 and 65, to the anodes of coupling diodes 66A, 66B and 66C,respectively.

The cathode of the first coupling diode 66A is connected to the lead 46and to the anode of the first SCR 41A via a lead 67. The cathode of thesecond coupling diode 66B is connected to the lead 48 and to the anodeof the second SCR 41B via a lead 68. The cathode of the third couplingdiode 66C is connected to the lead 51 and to the anode of the third SCR41C via a lead 69.

A switching control unit 71 controls the conductive condition of theswitching control transistor 59 and of each of the SCRs 41A, 41B and41C. The switching control unit 71 is thus connected to and provides acontrol signal to the base electrode of the switching control transistor59 via a lead 72 and to the control electrodeof each of the SCRs 41A,41B and 41C via leads 70A, 70B and 70C, respectively.

A computer 81 (FIG. 3) is connected to an input of the switching controlunit 71 via a lead 99 (FIG. 3) and to an input of a collator 95 (FIG. 3)via a lead 97 (FIG. 3). The connection and relation of the computer 81,the switching control unit 71 and the collator 95 are described withreference to FIG. 3. The output of the collator is connected to an inputof the shift register 14 (FIG. 1) via a lead 103 (FIG. 3). The shiftregister 14 is connected to and provides a control signal of the baseelectrode of each of the control transistors 19-1 to 19-h via acorresponding one of leads 73-1 to 73-11, respectively.

The printing operation is controlled either manuallyor automaticallysuch as, for example, via prerecorded program, through the computer 81and the switching control unit 71 and the collator 95 and shift register14. Although each of the SCRs or thyristors 41A, 41B and 41C is switchedto its conductive or ON condition by a sutficient current in its controlelectrode, the potential of its anode must be positive and higher inmagnitude than that of its cathode. Each of the SCRs 41A, 41B and 41C isswitched to its non-conductive or OFF condition by decreasing thepotential of the anode to a magnitude below that of the cathode.

The switching control unit 71, under the control of the computer 81,first switches the switching control transistor 59 to its conductive orON condition. When the switching control transistor 59 is in itsconductive condition, it maintains the potential of the anodes of theSCRs 41A, 41B and 41C positive and at a higher magnitude than that ofthe cathodes thereof and said SCRs can be switched ON by suflicientcurrent supplied to the control electrodes thereof. When the switchingcontrol transistor 59 is in its non-conductive condition, the potentialof the anodes of the SCRs 41A, 41B and 41C becomes equal to that of thecathodes thereof and said SCRs cannot be switched ON, but are, ratherswitched off.

As illustrated in FIG. 4A, the computer 81 supplies, via the switchingcontrol unit 71 and the leads 70A, 70B and 70C, successive switchingsignals to the control electrodes of the CSRs 41A, 41B and 41C. When aswitching signal is supplied to the control electrode of the first SCR41A, it provides sufiicient current to the control electrode of saidfirst SCR to switch said SCR to its conductive or ON condition. Thecomputer 81, via the collator 95 and the shift register 14, thenswitches the control transistors 19-1 to 19-h to their conductive or ONcondition, thereby closing an energizing circuit to the power source Efor the hammer-controlling electromagnets 16-1 to 16-h through the firstSCR 41A. This operation is then repeated for each of the second andthird areas of the type drum 11 (FIG. 1) by the switching of the secondand third SCRs 41B and 41C to their conductive conditions.

When the printing of the first area of the type drum 11 is completed,the second SCR 41B is switched to its conductive condition in theaforedescribed manner and the hammer-controlling electromagnets 17-1 to17-h of the second group of said electromagnets are energized and causethe printing of the second area of the type drum 11. Since only one ofthe three SCRs is energized or fired at one time, only one of said SCRsis in its conductive condition at one time, so that only one of thefirst, second and third areas 1, 2 and 3 is printed at one time. Uponcompletion of the second area of the type drum 11, the third SCR 41C isswitched to its conductive condition and energizes thehammer-controlling electromagnets 18-1 to 18-h in the aforedescribedmanner to print the third area of said type drum.

In the embodiment of the apparatus of FIG. 3, a computer 81 is directlyconnected to the line printer 82 without the interposition of a buttermemory unit. In the modification of FIG. 5, however, a buffer memoryunit is interposed between the computer 81 and the line printer. Thesame components of FIGS. 3 and 5 are indicated by the same referencenumerals therein. FIGS 4A and 4B are time charts illustrating theoperation of the embodiment of FIG. 3.

In FIG. 3, the line printer 82 comprises the type drum 11 (FIG. 1), theprint hammers 12 (FIG. I), and the hammer-controlling elec'tromagnets 83which include the electromagnets 16-1 to 16-h, 17-1 to 17-h and 18-1 to18-11 (FIG. 2). The line printer 82 also includes the hammer controlunit 13 and the shift register 14 (FIG. 1). A recording medium orprinting paper 84 is interposed between the type drum 11 and the printhammers 12 and is driven or moved by any suitable means (not shown inthe figures). The line printer also includes a diode circuit 85 whichincludes the various diodes such as, for eX- ample, the diodes 25, 26,27, 34, 35 and 36 (FIG. 2) and an SCR circuit 86 which includes thefirst, second and third SCRs 41A, 41B and 41C (FIG. 2). The switchingcontrol unit 71 (FIG. 2) is connected to the SCR circuit 86.

A type code and time pulse generator 87 is coupled to the type drum 11for rotation with said type drum. The output or time pulses of thegenerator 87 are supplied to the input of a time pulse detector 88 via alead 89 and to the input of an amplifier 91 via the lead 89 and a lead92. The output of the amplifier 91 is supplied to the input of a typecode register 93 via a lead 94 and the output of said register issupplied to an input of a collator 95 via a lead 96. Another input ofthe collator 95 is supplied, via a lead 97, by the computer 81.

The output of the detector 88 is applied to an input of the switchingcontrol unit 71 via a lead 98. Another input of the switching controlunit 71 is supplied by the computer 81 via a lead 99. An output of theswitching control unit 71 is connected to the hammer control unit 13 viaa lead 101 and to an input of the shift register 14 via the lead 101 anda lead 102. The output of the collator 95 is supplied to another inputof the shift register 14 via a lead 103. The output of the shiftregister 14 is supplied to an input of the hammer control unit 13 via alead 104. The output of the hammer control unit 13 is supplied via alead 105 and the diode circuit 85 to the hammer-controllingelectromagnets 83. The diode circuit 85 is connected to an output of theswitching control unit 71 via a lead 106, the SCR circuit 86 and a lead107.

FIGS. 4A and 4B illustrate the basic printing operation of the apparatusof the embodiment of FIG. 3. In each of FIGS. 4A and 4B, each of theline segments extends in the direction of the abscissa, which representstime. FIG. 4A illustrates the printing of one line having columns.

There are four basic orders involved in the printing of one line of 120columns, four basic orders include three printing orders P1, P2 and P3for the corresponding areas 1, 2 and 3 of the type drum 11 (FIG. 1),respectively. The fourth basic order is the feeding order F1 for therecording medium or paper 84 (FIG. 3).

as illustrated in FIG. 4A. The

The computer 81 provides the first printing order P1 for the printing ofthe first area 1 of the type drum 11 (FIG. 1) in the switching controlunit 71 via the lead 99 (FIG. 3). This switches the first SCR 41A ofFIG. 2 in the SCR circuit 86 (FIG. 3) to its conductive condition. Theinitial control signal supplied by the computer 81 simultaneously startsthe printing cycle R1 and said computer provides the printinginformation.

The type code corresponding to the type on the type drum 11 (FIG. 3) isindicated by the type code and time pulse generator 87 of FIG. 3 and isstored in the type code register 93 after amplification by the amplifier91 (FIG. '3). The type code stored in the register 93 is collated in thecollator 95 with the printing information supplied by the computer 81via the lead 97 and the result of the collation is stored in the shiftregister 14 (FIG. 3). Upon the completion of the collation of 40 columnsthe hammer control unit 13 is triggered by the next time pulse from thetype code and time pulse generator 87 and the result of the collation ofthe 40 columns is printed. The aforedescribed operation completes theprinting of one letter. The printing of the 40 columns of area 1 of thetype drum 11 (FIG. 1) is completed when all of the 64 letters of thetype drum (FIG. 4A) have been printed by the aforedescribed operationcommencing with the initiation of the transfer of printing informationand concluding with the printing.

When the first area 1 of the type drum 11 (FIG. 1) has been completelyprinted, the computer 81 (FIG. 3) provides the second printing order P2(FIG. 4A) for the rinting of the second area 2 of said type drum. Thesecond SCR 41B (FIG. 2) of the SCR circuit 86 of FIG. 3 is then switchedto its conductive condition, the first SCR 41A having been switched toits non-conductive condition upon the supply of the second printingorder P2 to the switching control unit 71 (FIG. 3). The second area 2 ofthe type drum 11 (FIG. 1) is then printed in the same manner as thefirst area 1 of said type dru-m. Upon completion of the printing of thearea 2 of the type drum 11, the third area 3 of said type drum (FIG 1)is then printed in the same manner as the areas 1 and 2, under thecontrol of the third printing order P3 from the computer 81.

When the printing of the third area 3 of the type drum 11 (FIG. 1) iscompleted, the printing of a single line is completed. The computer 81(FIG. 3) then provides the paper feeding order F1 and the paper is fedor moved to its next line position by suitable apparatus (not shown inthe figures). The printing cycle for one line is completed upon thecompletion of the feeding or moving of the printing paper 84 (FIG. 3) inresponse to the paper feeding order F1.

The time chart of FIG. 4B illustrates another arrangement of printingorders in the apparatus of FIG. 3. In the arrangement of printing ordersillustrated in FIG. 4B, the computer 81 provides the first printingorder P1. The first printing order P1 is then followed by paper feedingorders F1 and F2 which are followed by a repetition of the firstprinting order P1. After the completion of the printing R1 of the firstarea 1 of the type drum 11 (FIG. 1), a third paper feeding order F3 issupplied. The third paper feeding order F3 is followed by the secondprinting order P2.

The basic printing cycle of the apparatus of FIG. 3, illustrated in FIG.4B, avoids unnecessary printing time in the event of slippage in theprinting of the first area 1 of the type drum 11 since it involvesfeeding the paper twice (F1 and F2) so that said paper is moved twolines, print ing the first area 1 (R1) and feeding the paper by one line(F3) and printing the second area 2 (R2), and so on, as shown in FIG.4B. In a conventional line printing operation, where the printing andfeeding are controlled by a single order, the printing time for thesecond and third areas 2 and 3 of the type drum 11 (FIG. 1) is wasted ifonly the first area 1 is actually printed. Furthermore,

in such conventional line printer operation, the structure of the lineprinter is complex. In accordance with the method of the presentinvention, there are four independent orders which need not be in anyparticular succession with relation to each other, so that areas whichare not to be printed are not ordered to be printed by correspondingprinting orders. Thus, the next succeeding printing order is providedfor an area to be printed, so that there is no printing time wasted andhigh speed processing is accomplished.

In the modification of FIG. 5, a buffer memory in the form of a corememory, or other suitable memory device, is included in the line printerapparatus. Thus, in the modification of FIG. 5, an output of theswitching control unit 71 is connected to the input of a core memory 111via a lead 112, an inhibitor 113 and a lead 114. The output of the corememory 111 is connected to the input of a shift register 115 via a lead116. An output of the shift register 115 is connected to a second inputof the collator via a lead 117 and to an input of the switching controlunit 71 via the lead 117 and a lead 118.

As shown in FIG. 6A, a complete printing cycle R is accomplished bythree rotations of the type drum 11 (FIG. 5). The printing informationis provided by the computer 81 and the first printing order for printingthe first area 11 of the type drum 11 (FIG. 1) is supplied by saidcomputer. Both the printing information and the printing orders aresupplied by the computer 81 to the switching control unit 71 and arestored in the core memory 111. When the printing information for onecolumn has been completely transferred to the core memory 111, the lineprinter is in effect disconnected from the computer 81. When the firstprinting order P1 has been provided, the line printer initiates theprinting cycle R (FIG. 6A). The line printer thus first provides thefirst printing subcycle S1 by printing the first area 1 of the type drum11 (FIG. 6A), that is, the stored contents of the core memory 111 areread out via the shift register .115 and are collated by the collator 95with the type codes and are printed for the first 40 columns after thetyping of the 64 letters. The line printer then provides the secondprinting subcycle S2 (FIG. 6A) by printing the second area 2 of the typedrum 11. Upon completion of the second printing subcycle S2, the lineprinter provides the third printing subcycle S3 by printing the thirdarea 3 of the type drum 11 (FIG. 1).

The printing of the three areas of the type drum 11 (FIG. 1) iscompleted after said type drum has rotated three times. After threerotations, the printing cycle R is thus completed. The line printer thenprovides the paper feeding cycle F (FIG. 6A), and the recording mediumor printing paper 84 (FIG. 5) is fed or moved one line for the transferof the next succeeding printing information under the control of thesecond printing order P2 (FIG. 6A). The buffer memory 111 of themodification of FIG. 5 thus permits the printing of the three areas orgroups of columns of the type drum 11 to follow any desired sequence orpattern such as, for example, the conventional printing cycle of a lineprinter. If the conventional pr nting cycle is followed by the apparatusof FIG. 5, the printing time is three times the duration of the printingtime of a line printer following the conventional printing cycle inwhich a single line is printed by a single rotation of the type drum.

The extra printing time illustrated in FIG. 6A is eliminated when theapparatus of FIG. 5 is operated in accordance with the time chart ofFIG. 6B. In FIG. 6B, the end of the printing cycle R is indicated due tosupervision of the printing information independent of the rotation ofthe type drum. The supervision of the printing information may beprovided by signal bits, flag bits or other indicating or identifyingsignals, symbolically represented in FIG. 5 by cross-hatched strips onthe core memory 111 and the shift register 115. One signal bit is addedto the core memory 111 for each column. The signal bits permit thesupervision of the printing information and increase the printing speedby preventing the waste of printing time. The signal or flag bit and itsapplication is described in Japanese patent application Ser. No.Tokugansho 39-27124, filed May 14, 1964.

The computer 81 supplies the first printing order P1 (FIG. 6B) to theswitching control unit 71 (FIG. 5) and the printing information is alsosupplied to said switching control unit. At the same time a signal isrecorded as the flag bit of the column to be printed and a 1 signal isrecorded in the other columns. The line printer then provides the entireprinting cycle R by providing the printing subcycles S1, S2 and S3 (FIG.6B) in sequence.

Upon the provision of the first subcycle S1, the first area 1, of 40columns, of the type drum 11 (FIG. 1) is read out of the core memory 111and is printed. The con tents of the first area are read out of the corememory 111 and are collated with the type code by the collator 95, sothat the columns of the first area are printed in accordance with thetype code. The flag bit of the column printed is changed from 1 to 0 asthe printing of each column is completed. Each time the informationstored in the core memory 111 is read out, the flag bit is detected, andwhen all the flag bits of the group or area are detected as being 0, thefirst printing subcycle S1 is completed and the second printing subcycleS2 is initiated. The second and third printing subcycles S2 and S3 thenfollow in the same manner as the first printing subcycle S1 (FIG. 6B).

The signal bit or flag bit control system utilized in conjunction withthe core memory 111 thus completes a single printing subcycle within onerotation of the type drum 11 (FIG. 5), and when there is no printinginformation for an area, the only time utilized is that for reading out40 columns of the core memory 111, which time is approximately 100microseconds. The printing speed of the apparatus of FIG. 5 illustratedin FIG. 6B is thus twice that illustrated in FIG. 6A.

The flag bit or signal bit system for indicating the end of eachprinting subcycle of the printing cycle is described as one possiblemeans for such indication. In actuality, any suitable detectingarrangement may be utilized such as, for example, counting systems orthe like. Thus, the number of columns containing printing data orinformation may be counted in advance when the information istransferred to the switching control unit 71 (FIG. 5) and the number ofcolumns printed may be counted each time a column is printed. Theprinting cycle for the printing of all the columns is then indicated ascompleted when the number of columns actually printed is the same as thenumber of columns counted in advance.

FIG. 7 shows a line printer for a hammer which may be utilized as eachhammer of the apparatus of the present invention.

FIG. 8 shows a type wheel which may be utilized as the type wheel of theapparatus of the present invention.

FIG. 9 illustrates the type surface of a type wheel which may beutilized as the type wheel of the apparatus of the present invention.

FIG. 10 illustrates the data printed by the apparatus of the presentinvention on the printing paper of said apparatus. In FIG. 10, thehorizontal spaces indicate thirty columns divided into three groups orareas of ten each. The vertical spaces indicate the type printingcharacters or numbers of the type wheel and comprise the numerals 0 to9. The thirty columns are completely printed by the revolution of thetype wheel three times.

FIGS. 7, 8 and 9 are FIGS. 1, 2 and 3, respectively, of United StatesPatent No. 3,322,063, issued May 30, 1967.

While the invention has been described by means of specific examples andin specific embodiments, I do not wish to be limited thereto, forobvious modifications will occur to those skilled in the art withoutdeparting from the spirit and scope of the invention.

I claim:

1. Line printing apparatus, comprising printing means for printing aplurality of columns, said printing means including a plurality ofprinting hammers, hammer control means for controlling the operation ofsaid printing means to successively operate said plurality of printinghammers in groups to print groups of columns in succession, the numberof columns in each of the groups of columns being less than the totalnumber of said plurality of columns, said hammer control meanscomprising a plurality of hammer-controlling electromagnets eachcontrolling a corresponding one of said printing hammers, electricalpower supply means and switching means interposed between saidelectromagnets and said power supply means for selectively switching onegroup of electromagnets at a time to said power supply means, each groupof electromagnets being the same as each group of corresponding printinghammers.

2. Line printing apparatus as claimed in claim 1, wherein said switchingmeans comprises a plurality of semiconductor controlled rectifiersinterposed between said electromagnets and said power supply means forselectively switching one group of electromagnets at a time to saidpower supply means, and the number of said semiconductor controlledrectifiers is the same as the number of said groups.

3, Line printing apparatus as claimed] in claim 2, Wherein said hammercontrol means comprises switching control means connected to saidsemiconductor controlled rectifiers for controlling the conductivecondition of each thereof.

References Cited UNITED STATES PATENTS 2,080,649 5/1937 Breiting 101-962,770,188 11/1956 Nolan 101-93 2,787,953 4/1957 Sobisch et al 101-932,831,424 4/1958 MacDonald 101-111 X 3,007,399 11/1961 Sasaki et al101-93 3,064,561 11/1962 Maudit 101-93 3,157,115 11/1964 West et a1.101-93 3,175,486 3/1965 Athens et a1. 101-93 3,247,788 4/ 1966 Wilkinset a1. 101-93 WILLIAM B. PENN, Primary Examiner.

